Obesity now kills more people worldwide than car crashes, terror attacks, and Alzheimer's combined

Look around you, and it's not hard to see how serious the problem of obesity has become in America. People here are now bigger, and suffering from more obesity-related diseases, than ever before — prompting cities across the country to desperately try to fight back with measures like soda taxes and calorie labels.

Travel beyond the US borders, though, and you'll see the same problem elsewhere: Obesity is now a growing phenomenon in just about every corner of the world, in poor and rich countries alike.

That's the big take-home message from an impressive new study, published in the New England Journal of Medicine. A global group of researchers, funded by the Bill and Melinda Gates Foundation, came out with the best estimate yet on the worldwide obesity burden, and found that more than 10 percent of the world's population — 107.7 million children and 603.7 adults — is now obese.

Since 1980, the obesity prevalence has doubled in more than 70 countries around the world — mainly in low- and middle-income regions — and it has steadily increased in nearly every other country.

The study is the largest systematic analysis of obesity data ever done, with researchers combing the medical literature and crunching thousands of data sets on obesity in adults and children covering 195 countries. Here are their 5 most important takeaways.

1) The main driver of obesity is not lack of exercise

A lack of exercise and too many calories have been depicted as equal causes of the obesity crisis. But they shouldn't be, the NEJM authors said.

According to their paper, physical activity levels began to decline before the global obesity rate started to surge — which means changes to the food environment are the prime obesity culprit.

Food companies like PepsiCo and McDonalds have made inroads all over the world with their cheap, calorie-dense and nutrient poor soda, candy, and fast food. They've also heavily marketed their products — which are swiftly becoming cheaper and more accessible than healthier alternatives, like fruits and vegetables, particularly in cities.

"Increased availability, accessibility, and affordability of energy-dense foods, along with intense marketing of such foods, could explain excess energy intake and weight gain among different populations," the researchers wrote.

Yet, we often focus on the need for more exercise as the way to shrink our waistlines, and the study suggests that focus is misguided.

As Diana Thomas, a Montclair State University obesity researcher told Vox, "There are all kinds of reasons to exercise that are good for your health. However, if you're trying to lose weight, the biggest problem I see is food. We need to cut back the food we're eating."

Indeed, the evidence is now clear: Exercise is excellent for health, but it's not important for weight loss. The two things should never be given equal weight in the obesity debate.

2) Obesity contributed to 7 percent of all deaths globally in 2015

Having a high body weight is now considered a risk factor for a range of chronic diseases, including diabetes, cardiovascular disease, chronic kidney disease, and a number of cancers. And as obesity has become more common, so has the toll for these health problems.

Altogether, the researchers estimated that a high body weight contributed to 4 million deaths globally — or 7 percent of the deaths from any cause — in 2015. Most of those deaths were caused by cardiovascular disease, with diabetes following closely behind, along with kidney disease and cancers.

This is a massive number: It's more than the deaths caused by traffic accidents, Alzheimer's, or other deadly issues that get a lot of airtime, like terrorism, combined.

3) Childhood obesity is growing faster than adult obesity — and the US rate is one of the worst

While obesity is still rarer among children compared to adults, the rate of childhood obesity has surged much faster in many countries.

Of the 20 largest countries in the world, the US had the worst rate of childhood obesity, with 13 percent of children now obese. Egypt had the highest adult obesity prevalence, where 35 percent of adults are now obese.

"Even if we were to dramatically step up prevention efforts tomorrow," said Andrew Stokes, assistant professor of global health at Boston University's School of Public Health, "there is a generation of children, over 100 million globally, that will likely have to grapple their entire lives with weight-related diseases, such as diabetes and heart diseases and also face higher rates of premature mortality."

There was, however, a disconnect between the rise in obesity and the associated burden of disease in wealthy countries like the US, where the death rate linked to obesity has actually fallen over the past 20 years.

This isn't because obesity is any less dangerous here or now; it's because of advances in medicine that have helped people manage their high blood pressure and other cardiovascular problems, the researchers said. And unfortunately, those medicines aren't as widely available in the developing countries that are seeing the most extreme increases in obesity.

Many of the places where obesity is climbing the fastest — such as Mali, Burkina Faso, and Guinea-Bissau — have health care systems that "are not equipped to deal with this tsunami of [obesity-related] chronic conditions", Stokes added.

5) There are some countries where the obesity rate is still quite low. Here's how they could stay that way.

While no country has managed to cut its obesity levels, there are some countries where obesity rates remain low. The prevalence of obesity was lowest among adults in Vietnam, a middle-income country, and children in Bangladesh — a poor country where only a little over 1 percent of those populations are now obese.

Stokes saw this as a cause for optimism. "This adds urgency to finding solutions to the epidemic of obesity that can be implemented in these settings before rates rise as they have elsewhere," he said. Finding out what's different about these countries may also hold the keys to the root causes of the epidemic.

"Today, for the first time in history, more people are dying from too much unhealthy food than they are from too little healthy food," Mike Bloomberg, WHO Global Ambassador for Noncommunicable Diseases, said in a statement. "This is a global epidemic that governments can no longer ignore, because there are many steps that they can take to tackle obesity and save lives."

Countries are experimenting with policy solutions — but Trump may slow them down in the US

Many countries and states are experimenting with measures like soda taxes, curbing marketing of unhealthy foods to kids, and making school meals healthier, but we still don't have a firm grasp on which of these policies will work. And Americans can expect the Trump administration to delay when it comes to implementing these policies at the federal level.

So far, the new administration has been pushing back key federal policies that were aimed at curbing obesity. They've delayed the compliance deadline for calorie labels on restaurant menus, relaxed nutrition standards for federally subsidized school lunch programs, and pushed back implementation of newer and more informative Nutrition Facts labels, which were scheduled to appear on millions of food packages by July 2018.

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There is still cause for hope. As recently as 2013, the US had no soda taxes aimed at tamping down obesity rates. Now, nearly 9 million Americans live in cities and states with those taxes in place. So we are making some progress at the local level, even if the federal government ignores the epidemic.